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Cureus May 2024The outcome of an endodontic procedure determines the clinical success of the treated tooth. A post-endodontic restoration will restore the tooth's form, function, and...
The outcome of an endodontic procedure determines the clinical success of the treated tooth. A post-endodontic restoration will restore the tooth's form, function, and aesthetics while preserving and safeguarding its existing tooth structure. To restore endodontically treated teeth with the best possible tissue preservation, the least invasive preparation is the aim. Full-coverage crowns are still more popular than partial-coverage crowns. Conservative dental procedures such as inlays, overlays, and endocrowns maximize the amount of tooth structure that is intact while minimizing the amount of tooth structure that is removed. Compared to posts, cores, and crowns, endocrowns offer several advantages in terms of ease of preparation, application, and reduced clinical visits and time. Endocrown is a simple, minimally invasive preparation usually given when margins are supragingival, which makes it self-cleansable and maintains natural tooth contact, preventing interference with periodontal tissue. This case report focuses on managing endodontically treated teeth with the fabrication of endocrown using computer-aided design (CAD) and computer-assisted manufacturing (CAM) techniques.
PubMed: 38903384
DOI: 10.7759/cureus.60686 -
Contact Lens & Anterior Eye : the... Jun 2024Corneal techniques for enhancing near and intermediate vision to correct presbyopia include surgical and contact lens treatment modalities. Broad approaches used...
Corneal techniques for enhancing near and intermediate vision to correct presbyopia include surgical and contact lens treatment modalities. Broad approaches used independently or in combination include correcting one eye for distant and the other for near or intermediate vision, (termed monovision or mini-monovision depending on the degree of anisometropia) and/or extending the eye's depth of focus [1]. This report provides an overview of the evidence for the treatment profile, safety, and efficacy of the range of corneal techniques currently available for managing presbyopia. The visual needs and expectations of the patient, their ocular characteristics, and prior history of surgery are critical considerations for patient selection and preoperative evaluation. Contraindications to refractive surgery include unstable refraction, corneal abnormalities, inadequate corneal thickness for the proposed ablation depth, ocular and systemic co-morbidities, uncontrolled mental health issues and unrealistic patient expectations. Laser refractive options for monovision include surface/stromal ablation techniques and keratorefractive lenticule extraction. Alteration of spherical aberration and multifocal ablation profiles are the primary means for increasing ocular depth of focus, using surface and non-surface laser refractive techniques. Corneal inlays use either small aperture optics to increase depth of field or modify the anterior corneal curvature to induce corneal multifocality. Presbyopia correction by conductive keratoplasty involves application of radiofrequency energy to the mid-peripheral corneal stroma which leads to mid-peripheral corneal shrinkage, inducing central corneal steepening. Hyperopic orthokeratology lens fitting can induce spherical aberration and correct some level of presbyopia. Postoperative management, and consideration of potential complications, varies according to technique applied and the time to restore corneal stability, but a minimum of 3 months of follow-up is recommended after corneal refractive procedures. Ongoing follow-up is important in orthokeratology and longer-term follow-up may be required in the event of late complications following corneal inlay surgery.
PubMed: 38851946
DOI: 10.1016/j.clae.2024.102190 -
APMIS : Acta Pathologica,... May 2024The use of highly crosslinked ultra-high molecular weight polyethylene (XLPE) has significantly reduced the volumetric wear of acetabular liners, thereby reducing the...
Fourier-transform infrared spectroscopy imaging is a useful adjunct to routine histopathology to identify failure of polyethylene inlays in revision total hip arthroplasty.
The use of highly crosslinked ultra-high molecular weight polyethylene (XLPE) has significantly reduced the volumetric wear of acetabular liners, thereby reducing the incidence of osteolysis. However, contemporary components tend to generate smaller wear particles, which can no longer be identified using conventional histology. This technical limitation can result in imprecise diagnosis. Here, we report on two uncemented total hip arthroplasty cases (~7 years in situ) revised for periprosthetic fracture of the femur and femoral loosening, respectively. Both liners exhibited prominent wear. The retrieved pseudocapsular tissue exhibited a strong macrophage infiltration without microscopically identifiable polyethylene particles. Yet, using Fourier-transform infrared micro-spectroscopic imaging (FTIR-I), we demonstrated the prominent intracellular accumulation of polyethylene debris in both cases. This study shows that particle induced osteolysis can still occur with XLPE liners, even under 10 years in situ. Furthermore, we demonstrate the difficulty of determining the presence of polyethylene debris within periprosthetic tissue. Considering the potentially increased bioactivity of finer particles from XLPE compared to conventional liners, an accurate detection method is required, and new histopathological hallmarks of particle induced osteolysis are needed. FTIR-I is a great tool to that end and can help the accurate determination of foreign body tissue responses.
PubMed: 38741279
DOI: 10.1111/apm.13421 -
Clinical Oral Investigations May 2024To assess the long-term clinical performance of ceramic in-/onlays (CIOs) and cast gold partial crowns (CGPCs) in posterior teeth in terms of success, survival,...
OBJECTIVES
To assess the long-term clinical performance of ceramic in-/onlays (CIOs) and cast gold partial crowns (CGPCs) in posterior teeth in terms of success, survival, complications (biological, technical) and quality.
MATERIAL AND METHODS
In a retrospective study, a total of 325 patients were recorded after up to 24.8 years (mean 13.9 ± 3.8 years) having (pre-)molars restored with CIO (Empress I, Ivoclar Vivadent, n = 161) and CGPC (Degunorm, DeguDent, n = 164) by supervised undergraduate students. A total of 296 restorations were assessed clinically and radiologically in healthy and endodontically treated teeth using modified United States Public Health Service (USPHS) criteria. Cumulative success and survival rates of the restorations were calculated using Kaplan-Meier estimates. Biological and technical complications were recorded. Status of oral health comprising caries risk and localized periodontitis were assessed.
RESULTS
The cumulative success rates of CIOs were 92.1% and of CGPCs 84.2% after mean service times of 14.5 years. The annual failure rates of total service times were 0.5% in teeth restored with CIO (n = 155) and 0.7% in teeth restored with CGPC (n = 163). The cumulative survival rates of CIOs were 93.9% after a mean service time of 15.2 years and decreased to 91.7% after 23.5 years. The cumulative survival rates of CGPCs were 92.6% after a mean service time of 14.9 years and 91.8% after 23.5 years. Complications in CIOs (n = 149) were ceramic fracture (6.7%), secondary caries (4.7%), endodontic complication (2.7%) and tooth fracture (1.3%) compared to CGPCs (n = 147) with endodontic complication (8.8%), secondary caries (4.8%) and decementation (2.0%). Endodontically treated teeth restored with CIO or CGPC revealed significantly less often success compared with corresponding vital teeth (p = .02). CIOs and CGPCs revealed clinically and radiographically good and excellent qualities with 71.8% (107/149) and 68% (100/147) without any significant differences regarding type of restoration.
CONCLUSIONS
Both CIOs and CGPCs achieved high survival rates up to 24.8 years when performed by supervised undergraduate students. The longevity of the restorations may benefit from the intraoral repair of accessible defects and, in case of pulp infection or necrosis, an adequate endodontic management.
CLINICAL RELEVANCE
CIOs and CGPCs made by supervised undergraduate students are proper restoration types in posterior teeth in the long-term. An adequate preparation design, meticulous care in the inserting technique and constant biofilm removal due to proper oral hygiene combined with professional maintenance care are substantial. The clinical long-term performance was mostly limited by ceramic fractures in CIOs and endodontic complications in CGPCs.
Topics: Humans; Retrospective Studies; Crowns; Dental Restoration Failure; Female; Male; Adult; Inlays; Ceramics; Gold Alloys; Dental Caries; Dental Porcelain; Middle Aged; Dental Prosthesis Design; Tooth, Nonvital; Treatment Outcome
PubMed: 38702521
DOI: 10.1007/s00784-024-05682-7 -
Frontiers in Artificial Intelligence 2024Due to the high prevalence of dental caries, fixed dental restorations are regularly required to restore compromised teeth or replace missing teeth while retaining...
BACKGROUND AND OBJECTIVE
Due to the high prevalence of dental caries, fixed dental restorations are regularly required to restore compromised teeth or replace missing teeth while retaining function and aesthetic appearance. The fabrication of dental restorations, however, remains challenging due to the complexity of the human masticatory system as well as the unique morphology of each individual dentition. Adaptation and reworking are frequently required during the insertion of fixed dental prostheses (FDPs), which increase cost and treatment time. This article proposes a data-driven approach for the partial reconstruction of occlusal surfaces based on a data set that comprises 92 3D mesh files of full dental crown restorations.
METHODS
A Generative Adversarial Network (GAN) is considered for the given task in view of its ability to represent extensive data sets in an unsupervised manner with a wide variety of applications. Having demonstrated good capabilities in terms of image quality and training stability, StyleGAN-2 has been chosen as the main network for generating the occlusal surfaces. A 2D projection method is proposed in order to generate 2D representations of the provided 3D tooth data set for integration with the StyleGAN architecture. The reconstruction capabilities of the trained network are demonstrated by means of 4 common inlay types using a Bayesian Image Reconstruction method. This involves pre-processing the data in order to extract the necessary information of the tooth preparations required for the used method as well as the modification of the initial reconstruction loss.
RESULTS
The reconstruction process yields satisfactory visual and quantitative results for all preparations with a root mean square error (RMSE) ranging from 0.02 mm to 0.18 mm. When compared against a clinical procedure for CAD inlay fabrication, the group of dentists preferred the GAN-based restorations for 3 of the total 4 inlay geometries.
CONCLUSIONS
This article shows the effectiveness of the StyleGAN architecture with a downstream optimization process for the reconstruction of 4 different inlay geometries. The independence of the reconstruction process and the initial training of the GAN enables the application of the method for arbitrary inlay geometries without time-consuming retraining of the GAN.
PubMed: 38690195
DOI: 10.3389/frai.2024.1339193 -
The Journal of Prosthetic Dentistry Jun 2024More data are needed on the influence of preparation design on the fracture strength, failure type, repairability, and polymerization-induced cracks of molar teeth...
STATEMENT OF PROBLEM
More data are needed on the influence of preparation design on the fracture strength, failure type, repairability, and polymerization-induced cracks of molar teeth restored with direct composite resin restorations.
PURPOSE
This in vitro and finite element analysis study investigated the effect of different preparation designs on fracture strength, failure type, repairability, tooth deformation, and the formation of polymerization-induced cracks of compromised molars restored with direct composite resin restorations.
MATERIAL AND METHODS
Human molars (n=64) were randomly assigned to 4 different preparation designs: undermined inlay (UI), extended inlay (EI), restricted overlay (RO), and extended overlay (EO). The teeth were restored using direct composite resin and subjected to artificial thermomechanical aging in a mastication simulator, followed by load-to-failure testing. Three-dimensional (3D) finite element analysis was conducted to assess tooth deformation. Polymerization-induced cracks were evaluated using optical microscopy and transillumination. The fracture strength data were analyzed using a Kruskal-Wallis test, while the failure mode, repairability, and polymerization cracks were analyzed using the Fisher exact test (α=.05).
RESULTS
All specimens withstood thermomechanical aging, and no statistically significant difference in fracture strength was observed among the 4 preparation designs (P>.05). The finite element analysis showed differences in tooth deformation, but no correlation was observed with in vitro fracture resistance. The RO and EO groups presented significantly more destructive failures compared with the UI and EI groups (P<.01). The RO group had significantly fewer repairable failures than the UI and EI groups (P=.024). A correlation was found between higher frequencies of repairability and higher tooth deformation. A significant correlation between the increase in microfractures and preparation design was observed (P<.01), with the UI group exhibiting a higher increase in microfracture size compared with the EO group (P<.05).
CONCLUSIONS
No influence of preparation design on the fracture strength of compromised molars restored with direct composite resin restorations was evident in this study, but the failure mode of cusp coverage restorations was more destructive and often less repairable. The finite element analysis showed more tooth deformation in inlay preparations, with lower stresses within the root, leading to more reparable fractures. Since cusp coverage direct composite resin restorations fractured in a more destructive manner, this study suggests that even a tooth with undermined cusps should be restored without cusp coverage.
Topics: Composite Resins; Finite Element Analysis; Humans; Molar; Dental Restoration Failure; Dental Restoration, Permanent; Dental Stress Analysis; Tooth Fractures; In Vitro Techniques; Inlays; Materials Testing; Polymerization
PubMed: 38670907
DOI: 10.1016/j.prosdent.2024.03.039 -
Dentistry Journal Apr 2024The aim of this in vitro study was to compare the quality of marginal sealing at the cervical margins of indirect and direct composite resin restorations in...
INTRODUCTION
The aim of this in vitro study was to compare the quality of marginal sealing at the cervical margins of indirect and direct composite resin restorations in mesio-occluso-distal (MOD) cavities.
MATERIAL AND METHOD
MOD preparations were performed on 30 extracted teeth. The mesial cervical margin of each tooth was relocated using a flow composite resin (Enamel Plus HRi Flow, Micerium, Avegno, GE, Italy), then the samples were divided into three groups. In group A, the cavities were directly restored using a nanohybrid composite resin (Miris 2 Coltène Whaledent, Altstaetten, Switzerland) and a universal adhesive (ScotchBond Universal, 3M ESPE, St. Paul, MN, USA) by the etch-and-rinse strategy, for group B, the restoration procedure was similar but the self-etch strategy was used, and the samples in group C were filled using the inlay technique. Each sample was stored for 48 h in a 2% methylene blue solution, then it was cut in a mesio-distal direction using a Struers Secotom 50 device (Cleveland, OH, USA). The marginal sealing and adhesive interface were assessed for each sample at the cervical margin by optical microscopy (OM) and scanning electron microscopy (SEM). One-way ANOVA and Bonferroni post-hoc tests were used with a significance level of 0.05.
RESULTS
Significant differences were recorded within groups A and C, between mesial and distal margins ( = 0.02 in group A and = 0.043 in group C).
CONCLUSIONS
The marginal sealing is more effective in MOD inlay restoration compared to direct restorations. Relocation of the cervical margin with flow composite resin and the use of different adhesive strategies do not improve the marginal sealing.
PubMed: 38668004
DOI: 10.3390/dj12040092 -
Dental Materials Journal Jun 2024This study aimed to evaluate the effects of different resin-coating technique strategies and dual-cure resin luting materials on proximal marginal adaptation and the...
This study aimed to evaluate the effects of different resin-coating technique strategies and dual-cure resin luting materials on proximal marginal adaptation and the microtensile bond strengths (μTBSs) of CAD/CAM hybrid ceramic inlays. Extracted human molars were classified into four groups, depending on the coating technique: No coating (None), single coating (1-coating), double coating (2-coating), and flowable resin-coating (Combination). The inlays were bonded with one of the three materials: Panavia V5 (V5), Rely X Ultimate (RXU), and Calibra Ceram (CC). The differences with regard to adaptation were not significant. In the case of μTBS data for V5, no significant differences were observed, whereas for RXU, μTBS values for Combination statistically exceeded those for None and 1-coating. For CC, μTBS values for Combination statistically exceeded those for None, 1-coating, and 2-coating. The coating techniques did not influence the adaptation but influenced the bond strength, and Combination performed the best.
Topics: Inlays; Computer-Aided Design; Humans; Materials Testing; Tensile Strength; Ceramics; Dental Marginal Adaptation; Dental Bonding; Surface Properties; Resin Cements; Molar; In Vitro Techniques; Dental Stress Analysis; Dental Porcelain
PubMed: 38644215
DOI: 10.4012/dmj.2023-182 -
Contact Lens & Anterior Eye : the... Apr 2024It is important to be able to measure the range of clear focus in clinical practice to advise on presbyopia correction techniques and to optimise the correction power....
It is important to be able to measure the range of clear focus in clinical practice to advise on presbyopia correction techniques and to optimise the correction power. Both subjective and objective techniques are necessary: subjective techniques (such as patient reported outcome questionnaires and defocus curves) assess the impact of presbyopia on a patient and how the combination of residual objective accommodation and their natural DoF work for them; objective techniques (such as autorefraction, corneal topography and lens imaging) allow the clinician to understand how well a technique is working optically and whether it is the right choice or how adjustments can be made to optimise performance. Techniques to assess visual performance and adverse effects must be carefully conducted to gain a reliable end-point, considering the target size, contrast and illumination. Objective techniques are generally more reliable, can help to explain unexpected subjective results and imaging can be a powerful communication tool with patients. A clear diagnosis, excluding factors such as binocular vision issues or digital eye strain that can also cause similar symptoms, is critical for the patient to understand and adapt to presbyopia. Some corrective options are more permanent, such as implanted inlays / intraocular lenses or laser refractive surgery, so the optics can be trialled with contact lenses in advance (including differences between the eyes) to better communicate with the patient how the optics will work for them so they can make an informed choice.
PubMed: 38641525
DOI: 10.1016/j.clae.2024.102156 -
Journal of Pharmacy & Bioallied Sciences Feb 2024Surface roughness of the crowns is dependent on the pattern material used for the making as well as the procedure of investing. The study was aimed to examine the impact...
INTRODUCTION
Surface roughness of the crowns is dependent on the pattern material used for the making as well as the procedure of investing. The study was aimed to examine the impact of various pattern materials and investment procedures on the surface roughness of nickel-chromium alloy raw castings.
MATERIALS AND METHODS
An study was piloted at a tertiary care hospital. Eighty samples of inlay wax and pattern resin were divided equally. They were invested in phosphate-bonded investment material and kept under normal atmospheric pressure as well as invested under a pressure of 3 bars. The surface roughness was calculated with a Profilometer. The values obtained were compared using statistical tools keeping < 0.05 as significant.
RESULTS
Lowest surface roughness was seen for the wax pattern invested under positive pressure. While the highest was seen for the resin patterns invested at room pressure. A significant variance between the wax 1 and wax 2 ( < 0.01); as well as between the wax 2 vs. Resin 2 specimens ( < 0.01) was noted.
CONCLUSIONS
Wax patterns can be suggested as the material and method of choice because they showed the least amount of surface roughness when placed under pressure. Resin patterns when invested under pressure can also be suggested as an alternate as they also exhibited similar surface roughness as that of the wax.
PubMed: 38595557
DOI: 10.4103/jpbs.jpbs_445_23